I installed my first clutch in 1962, and didn't mark anything. Maybe it's a habit by now, but I've been getting away without marking them ever since. I can't really see any advantage to doing that, unless the assembly has been spin-balanced in one position. Even then, I think position would make little, if any difference.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!